We will study the process of recovery, both spontaneous and assisted, of sensory neglect and other specific motor and cognitive behaviors after surgically produced cerebrocortical injuries in monkeys. We will assay the attendant deficits and recovery by: (1) behavioral testing; (2) positron emitting transaxial tomography (PETT) with the animal in the awake performing condition; (3) 14C-deoxyglucose autoradiography (DG) and light microscopy after sacrifice. Specifically, normal animals will receive PETT scans prior to and following unimanual training on contingent motor response tasks. Subjects will then receive unilateral association cortical removals known to produce the contralateral neglect syndrome. At specific times during recovery from neglect, standardized behavioral tests and PETT scans will be given. Selected animals will be sacrificed for DG studies. After completion of spontaneous recovery, assistance in the form of retraining to task will be given to remaining animals. Taken together, the proposed study should allow us to determine (1) anatomic location of the functional changes associated with spontaneous and assisted recovery from well studied cortical function deficits; (2) correlate in detail the PETT findings with DG findings and light microscopy for each subject and for each stage of recovery; thus, (3) thoroughly explore the potential of PETT scanning as a tool for studying the neural substrate of evolving, dynamic, cognitive processes in the awake behaving subject with a view to optimizing the use of PETT scanning for such uses in human patients.